In a recyclic SAR ADC, the open loop gain can change from 24 to 212, and bandwidth requirements can also change from cycle to cycle. Thus, it is difficult to provide an amplifier that is stable with such variations in both gain and bandwidth. Some examples of conventional circuit are: U.S. Pat. Nos. 6,275,104; 6,486,820; 6,577,185; 7,193,545; 7,227,481; 7,342,449.